P.T.O.
Total No. of Questions—8] [Total No. of Printed Pages—4+1
Seat
No.[4757]-1042
S.E. (E & TC/Electronics)
(First Semester) EXAMINATION, 2015
SIGNALS AND SYSTEMS
(2012 PATTERN)
Time : Two Hours Maximum Marks : 50
N.B. :— (i) Attempt four questions as Question Nos. 1 or 2, 3 or 4,
5 or 6, 7 or 8.
(ii) Neat diagrams must be drawn wherever necessary.
(iii) Figures to the right indicate full marks.
(iv) Use of calculator is allowed.
(v) Assume suitable data if necessary.
1. (a) Perform the following operations on the given signal x(t) which
is defined as : [4]
x(t) = –t , –4 < t < 0
t , 0 < t < 2
0 , elsewhere
(i) Sketch the signal x(t)
(ii) Sketch z(t) = x(–t – 1).
[4757]-1042 2
(b) Determine whether the following signals are periodic or not,
if periodic find the fundamental period of the signal : [4]
(i) x(t) = cos (2t) + sin (2t)
(ii) x[n] = cos8
15
n�� �� �� � .
(c) Determine the step response of the following systems whose
impulse response is : [4]
h(t) = e–5tu(t).
Or
2. (a) Compute the convolution integral by graphical method and sketch
the output for [6]
x1(t) = 1, 0 < t < 2
0 otherwise
x2(t) = e–2tu(t).
(b) Find even and odd component of
(i) x(t) = u(t)
(ii) x(t) = sgn(t). [4]
(c) Determine the whether following signal is periodic or not, if
periodic find the fundamental period of the signal [2]
x(t) = cos2(2�t).
[4757]-1042 3 P.T.O.
3. (a) Find the trigonometric Fourier series for the periodic signal
x(t). Sketch the amplitude and phase spectra [6]
(b) A signal x(t) has Laplace transform
2
1X( )
4 5
ss
s s
�
� � .
Find the Laplace transform of the following signals :
(i) y1(t) = t x(t)
(ii) y2(t) = e–tx(t). [6]
Or
4. (a) Find the Fourier transform of x(t) = rectt� �
� �� � and sketch the
magnitude and phase spectrum. [6]
(b) Find the transfer function of the following : [6]
(i) An ideal differentiator
(ii) An ideal integrator
(iii) An ideal delay of T second.
x(t)
[4757]-1042 4
5. (a) Find the following for the give signal x(t) :
(i) Autocorrelation
(ii) Energy from Autocorrelation
(iii) Energy Spectral Density :
x(t) = Ae–atu(t). [6]
(b) Determine the cross correlation between two sequences which
are given below : [4]
x1(n) = {1 2 3 4}
x2(n) = {3 2 1 0}
(c) State and describe any three properties of Energy Spectral
Density (ESD). [3]
Or
6. (a) Prove that autocorrelation and energy spectral density form
Fourier transform pair of each other and verify the same for
x(t) = e–2tu(t). [9]
(b) State and explain any four properties of Power Spectral Density
(PSD). [4]
7. (a) Explain Gaussian probability model with respect to its density
and distribution function. [4]
(b) Two cards drawn from a 52 card deck successively without
replacing the first : [4]
(i) Given the first one is heart, what is the probability that
second is also a heart ?
(ii) What is the probability that both cards will be
hearts ?
[4757]-1042 5 P.T.O.
(c) A coin is tossed three times. Write the sample space which
gives all possible outcomes. A random variable X, which represents
the number of heads obtained on any double toss. Draw the
mapping of S on to real line. Also find the probabilities of
X and plot the C.D.F. [5]
Or
8. (a) A random variable X is fx(X) = 5X2 ; 0 < x < 1
= 0 ; elsewhere
Find E[X], E[3X – 2], E[X2]. [6]
(b) A student arrives late for a class 40% of the time. Class meets
five times each week. Find :
(i) Probability of students being late for at three classes
in a given week.
(ii) Probability of students will not be late at all during a
given week. [4]
(c) State the properties of Probability Density Function (PDF). [3]
P.T.O.
Total No. of Questions—8] [Total No. of Printed Pages—4
Seat
No.[4757]-1043
S.E. (E&TC/Electronics) (I Sem.) EXAMINATION, 2015
ELECTRONIC DEVICES AND CIRCUITS
(2012 PATTERN)
Time : Two Hours Maximum Marks : 50
N.B. :— (i) Attempt Q. No. 1 or Q. No. 2, Q. No. 3 or
Q. No. 4, Q. No. 5 or Q. No. 6, Q. No. 7 or
Q. No. 8.
(ii) Neat diagrams must be drawn wherever necessary.
(iii) Figures to the right indicate full marks.
(iv) Use of calculator is allowed.
(v) Assume suitable data if necessary.
1. (a) List the sources of instability of collector current. Explain self-
bias circuit in detail. [6]
(b) The transistor in the given circuit is connected as a common
emitter amplifier. Calculate Av, Ri, Ro. Refer Fig. 1.
Assume hie = 1.1 k�, hfe = 50, hre = 2.5 × 10–4,
hoe = 1/40 k. [6]
Fig. 1
[4757]-1043 2
Or
2. (a) Write a short note on thermal runaway. Explain thermal
stability. [6]
(b) Describe the method to increase the input resistance using
Darlington connection. [6]
3. (a) Draw and explain hybrid-� common emitter transistor
model. [6]
(b) In Colpitts oscillators L2 = 5 �H, C1 = C2 = 0.001 �F. What
will be the frequency of oscillations. If value of inductor is
doubled what will be frequency of oscillations ? What should
be the value of inductor to get frequency double to that of
original frequency ? [6]
Or
4. (a) For three stage RC coupled amplifier overall upper 3 dB
frequency is 16 kHz and overall lower 3 dB frequency
is 25 Hz. What are the values of FL and FH for each
stage ? Assume all stages identical. Also calculate bandwidth
of each stage. [6]
(b) Draw and explain various topologies of negative feedback. [6]
5. (a) What is cross over distortion ? Describe a method to minimize
this distortion. [6]
(b) A class-A amplifier operates from VCC = 20 V, draws a no
signal current of 5 Amp and feeds a load of 40 �, through
a step up transformer of 2
1
N
N = 3.16. Find :
(i) Whether the amplifier is properly matched for maximum
power transfer ?
(ii) Maximum a.c. signal power output.
(iii) Maximum d.c. power input.
(iv) Conversion efficiency at maximum signal input. [7]
[4757]-1043 3 P.T.O.
Or
6. (a) Draw and explain complementary symmetry class-B power
amplifier. [6]
(b) A power amplifier supplies 3 watt to a load of 6 k�. The
zero signal d.c. collector current is 55 mA and the collector
current with signal is 60 mA. How much is the percentage
second harmonic distortion ? [7]
7. (a) Explain the following non-ideal current voltage characteristics
of MOSFET :
(i) Body effect
(ii) Temperature effects
(iii) Breakdown effects. [6]
(b) Calculate the drain current and drain to source voltage of
a common source circuit with an N-channel EMOSFET shown
in Fig. 2. Find the power dissipated in the transistor.
Given VTN = 1 V and Kn = 0.1 mA/V2. [7]
Fig. 2
[4757]-1043 4
Or
8. (a) Determine the small signal voltage gain for a CS amplifier
shown in Fig. 3. Transistor parameters are VTN = 2 V,
Kn = 0.5 mA/V2 and � = 0. Assume the transistor is biased
such that IDQ = 0.4 mA. [7]
Fig. 3
(b) Write a short note on Bi-CMOS technology. [6]
Total No. of Questions—8] [Total No. of Printed Pages—4+2
[4757]-1044
S.E. (Electronics & E & TC) (First Semester)
EXAMINATION, 2015
NETWORK THEORY
(2012 Pattern)
Time : Two Hours Maximum Marks : 50
N.B. :— (i) Neat diagrams must be drawn wherever necessary.
(ii) Figures to the right indicate full marks.
(iii) Use of logarithmic tables, slide rule, Mollier charts, electronic
pocket calculator and steam tables is allowed.
(iv) Assume suitable data, if necessary.
1. (a) Obtain Thevenin and Norton equivalent circuits for the network
shown in fig. 1. [6]
Fig. 1
P.T.O.
Seat
No.
[4757]-1044 2
(b) For the graph and tree given in Fig. 2. find complete incidence
matrix, tieset matrix and F-cutset matrix : [6]
Graph Tree
Fig. 2
Or
2. (a) For the network shown in Fig. 3, determine the current I2 using
superposition theorem. [6]
Fig. 3
[4757]-1044 3 P.T.O.
(b) For the given incidence matrix, draw oriented graph and deter-
mine number of possible trees. [6]
1 1 1 0 0 0
A = 0 1 0 1 1 0
0 0 1 1 0 1
�� �� �� �� �� ��� �
3. (a) Find the expression for Vc(t) in the network shown in
Fig. 4. [6]
Fig. 4
(b) A series resonant circuit consists of R = 10 �, L = 100 mH and
C = 10 nF. Find resonant frequency �r, Fr, quality factor Qr at
resonant frequency, bandwidth. Also find current flowing through
circuit at resonance if the applied voltage is 100 V. [6]
[4757]-1044 4
Or
4. (a) For the network shown in Fig. 5, obtain the expression for
iL(t). [6]
Fig. 5
(b) A parallel resonant circuit has a coil of 100 �H with Q factor
of 100 and is resonated at 1 MHz. Find : [6]
(i) Capacitance
(ii) Resistance of coil
(iii) Bandwidth
(iv) Impedance at parallel resonance
5. (a) A Pi-section constant K filter consists of series arm inductance
of 20 mH and two shunt arm capacitors of 0.1 �F each. Calculate
cut-off frequency, attenuation at 1.5 kHz. Also find nominal
impedance Z� at f = 0 and f = fc. [7]
[4757]-1044 5 P.T.O.
(b) For a T-section symmetrical network derive the expression for
Zoc, Zsc and characteristic impedance Zo. [6]
Or
6. (a) For the system with 500 � resistance design T and Pi attenuators
to have 100 dB attenuation. Also draw T and Pi attenuators
showing the designed component values. [7]
(b) Draw the T section and Pi section contant K Band pass filter
circuits and write equations for components in series arm and
shunt arm. [6]
7. (a) Explain different network functions for one port and two port
networks. [7]
(b) Determine Z parameters for the network shown in Fig. 6. [6]
Fig. 6
[4757]-1044 6
Or
8. (a) Determine the impedance function Z(s) for the network shown
Fig. 7. Also draw its pole zero plot. [7]
Fig. 7
(b) Determine Y parameters of the network shown in Fig. 8. [6]
Fig. 8
P.T.O.
Total No. of Questions—8] [Total No. of Printed Pages—3
Seat
No.[4757]-1045
S.E. (E&TC/Electronics) (First Semester) EXAMINATION, 2015
DATA STRUCTURE AND ALGORITHM
(2012 PATTERN)
Time : Two Hours Maximum Marks : 50
N.B. :— (i) Neat diagrams must be drawn wherever necessary.
(ii) Figures to the right indicate full marks.
(iii) Assume suitable data if necessary.
1. (a) What do you mean by recursive function ? Explain with
example. [6]
(b) Write a C function for insertion sort to sort integer numbers. [6]
Or
2. (a) Explain parameter passing by value and passing parameter by
reference with suitable example. [6]
(b) What is pointer ? What are the advantages of using pointer ?
Explain pointer declaration and its initialization with an
example. [6]
3. (a) What is singly linked list ? Write C function for inserting
a node at a given location into a Singly Linked List. [6]
[4757]-1045 2
(b) Evaluate the following postfix expression using stack
623 + – 382/+ * 2�.
Note : � stands for power and all operands are single digit. [7]
Or
4. (a) Write short notes on :
(i) Circular Linked list and
(ii) Doubly linked list. [6]
(b) What is priority queue ? Explain its implementation using any
one method. [7]
5. (a) What is Binary Search Tree (BST) ? Write C functions for :
(i) Finding the smallest number in BST
(ii) Recursive inorder traversal of BST. [7]
(b) What is AVL Tree ? Define balance factor. Explain RR rotation
with an example. [5]
Or
6. (a) What is Binary Search Tree (BST) ? Construct a BST for
the following numbers :
27, 42, 43, 17, 39, 31, 10, 9, 19, 54, 33, 48.
Show all the steps. Write its preorder traversal. [8]
(b) Explain threaded binary tree with an example. What is its
advantage ? [4]
[4757]-1045 3 P.T.O.
7. (a) Write C function to implement Depth First Search traversal
of a graph implemented using adjacency matrix. [6]
(b) What do you mean by indegree and outdegree of a vertex
in a graph ? Write a C function to find indegree and outdegree
of vertex in a graph implemented using adjacency matrix. [7]
Or
8. (a) Define the term Graph. With the help of suitable example
give adjacency matrix representation and adjacency list
representation of a graph. [7]
(b) What do you mean by spanning tree of a graph ? Find the
minimal spanning tree of the following graph using Kruskal’s
algorithm. (Refer Fig. 1) [6]
1 2
3
5 4
6
16
21
11
33
19
5
6
18
10
14
Fig. 1
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